Auto-Equip Elytra on chestplate slot, & Editing Flight duration of fireworks

[dallin1016]

I'm making an arena focused on Elytra, and there are a couple issues I had with the class I made.

Firstly, Elytra do not auto equip into the chestplate slot, is there any way to do this with the current plugin?

Secondly, Is it possible to edit the flight duration of fireworks given with the class? I would like them to be flight duration 3, but they are one by default, and need NBT data to edit flight duration.